The present invention relates to an image communication/bidirectional broadcast system such as a broadband ISDN or a cable television, and in particular, to an advertisement or commercial base bidirectional broadcast system capable of coping with various needs of subscribers for programs and advertisement.
In the broadband ISDN, it is possible to comprehensively handle multimedia information ranging from a motion picture to data based on the asynchronous transfer mode (ATM). Research and development of the network system have been conducted in various countries at present, and this system is expectedly considered to reform or renovate the conventional broadcasting systems because of its capability of transmitting motion pictures. In particular, attentions have been paid to an arbitrary program access function and a high definition television image transmission through a broadband transmission.
FIG. 3 shows an example of such a broadcasting system. This configuration includes a head end or a broacasting station 115, which comprises, in association with a program source, a realtime broadcasting source 101 associated with retransmission of the conventional television broadcasting and satellite broadcasting and the broadcasting of programs resident within that station, a motion picture program data base 102 disposed to transmit in response to a request from a subscriber a motion picture program and/or still picture information to the subscriber system, a program transmitting apparatus 103, a still picture data base 104, a still picture transmitting apparatus 105, and a main control apparatus 106 for effecting communications of control information with subscribers so as to control the constituent elements above.
In association with the program transmission and exchange, there are provided an image encoder for achieving a bandwidth compression on a motion picture program signal 1, a broadcast signal 6, and a still picture signal 13; a cell assembler 108 for assembling an encoded (compressed) video signal 8 into a cell (information packet) and for adding thereto a header (logical channel number or destination) to establish a connection to a broadband transmission line 19 related to the pertinent subscriber, and an asynchronous transfer mode (ATM) exchange 109 for connecting the cell to a predetermined broadband transmission line 19 depending on the header of the cell.
Of the control information items 4, a down-link information item is transformed into a cell by means of the cell assembler 108 so as to be fed as a down-link control information cell to the ATM exchange 109. On the other hand, an up-link control information cell 21 is processed by the cell disassembler 110 such that the header thereof is removed so, thereby transferring post-control information 4 concatenated with predetermined data to the main control unit 106.
A subscriber system 116 disposed for each subscriber includes a network terminal 111 for supervising an interface with the head end 115 so as to achieve the assemble and disassemble operations of cells, a decoder 112 for decoding the encoder or coded video signal 8 (through a bandwidth compression), a television monitor 114, and a terminal controller 113 for controlling the constituent elements above and for communicating control information of the broadcast station with the subscriber.
The broadcast system above, however, is not structured in a broadcast configuration of an advertisement or commercial base which is established by developing the present broadcast system. In consequence, it is not possible to use a great amount of advertisement fee from the sponsors of the advertisement for the costs necessary to produce programs, to operate the system, and to install and to maintain broadcast equipment, and hence a high charge is imposed on the subscribers. In addition, for a considerable volume of information supplied by the system, the accessibility of the users to desired programs have not been actually facilitated and there still remains problem of practicability to be solved.
On the other hand, in the cable television system (CATV) developed mainly in the United States of America, the market has been developed through a basic service in which insertion of commercial or advertisement is effected without charge and there has been satisfied a certain degree of selectivity by use of about 50 channels.
FIG. 4 shows an example of the broadcast system including a head end (broad cast station) 111, which comprises, like in the case of FIG. 3, a realtime broadcast source 101, a motion picture data base 102, a program transmit apparatus 125, a main controller 118 for generating a program schedule signal 126 of the motion picture program so as to effect a charge operation of the program for the subscriber, and a modulator/mixer distributor 119 for modulating the program signal 4, the broadcast signal 6, and control signal 4 to produce a frequency multiplexed signal so as to distribute the signal to a plurality of broadcast transmission lines 5.
On the other side, there are disposed subscriber systems 120 each including a directional filter 121 for transmitting a down-link signal such as the broadcast signal to a receiver 123 and for bidirectionally transmitting a terminal control signal 8, a modulator/demodulator 122 for modulating and for demodulating the terminal control signal 8, a terminal controller 124 for producing control information such as a channel selection and up-link control information (for example, enquiry for a charging state and questionnaire about a program), a receiver 123 for demodulating the broadcast signal to obtain a program video signal of a baseband, and a television monitor 114.
This system possesses a function which is less sophisticated as compared with the system of FIG. 3 because of the reduced number of, namely, about 50 channels allowed for the system. That is, for example, for the program transmission from the motion picture data base, there can be repeatedly achieved broadcasting of only one to three kinds of programs through a channel according to a schedule specified by the head end. In consequence, the subscribers are required to select programs in the limited conditions of the contents of programs and in the restricted period of time.
Furthermore, since advertisement cannot be inserted in accordance with desires of the subscribers, a high subscription fee is charged on the subscribers because the advertisement is not taken into consideration in the broadcast system (about ten dollars (1300 Yen) per movie film in 1987).
On the other hand, for a charge-free basic service inserted with advertisement or commercial, it is only possible for the subscribers to select desired programs from several tens of channels.
In this situation, it is impossible to cope with various requirements of the subscribers with respect to the program and amount/quality of commercial.
As general articles related to the cable television system, there have been known (2) and (3) below; whereas an article (1) describes the broadband ISDN.
(1) Commentary: "ISDN Concept of Next Generation", Nikkei Electronics, No. 438, Jan. 11, 1989, p.p. 121-137.
(2) "CATV" supervised by H. Miyagawa, the Society of Electronics and Communications Engineers of Japan, Ohmsha, 1986.
(3) "Takeoff of New CATV", CATV Study Documentation Center, Telecom, 1986.
Conventionally, in the bandpath ISDN broadcast system, there have not been provided means for processing advertisement important with respect to the practice and for effecting an easy access to a desired program stored in a data base of a great capacity.
On the other hand, in the cable television system of the prior art, there has not been disposed means for effectively utilizing the limited number of channels, namely, about 50 channels so as to meet the various requests of subscribers for the advertisement and programs.